CVE-2026-121629: Red Hat GStreamer's adaptive streaming demuxers (HLS Security Vulnerability

A flaw was found in GStreamer's gst-plugins-good, specifically in the H.264 RTP depayloader element. When processing MTAP16 or MTAP24 multi-time aggregation RTP packets, a signed/unsigned integer conversion error causes the remaining-length counter to underflow to a large positive value when the packet is truncated. This allows a remote, unauthenticated attacker to trigger an out-of-bounds heap read of up to approximately 64 KiB of process memory by sending a single malformed RTP packet. Successful exploitation can crash the receiving GStreamer pipeline (denial of service), and in relay or transcoding deployments where output is accessible to the attacker, may expose adjacent heap contents.

A flaw was found in the Keycloak server's client management component. When a client is created or imported with authorization services enabled, the system fails to properly clear an internal session attribute used during the setup process. This allows an authenticated attacker with client management permissions to bypass security controls and upload a malicious JavaScript policy, which is then executed on the server when an authorization request is made. Successful exploitation could allow the attacker to run arbitrary code on the server, potentially compromising the entire system.

A flaw was found in OpenShift Pipelines-as-Code (PAC). PAC does not verify whether the creator of a Repository custom resource has permission to create PipelineRuns. A namespace user with only Repository and Secret create/delete permissions can cause PAC to execute attacker-controlled PipelineRuns as the auto-provisioned pipeline ServiceAccount, which carries ClusterRole/edit by default. This results in namespace-scoped privilege escalation, enabling Secret read, resource creation/modification/deletion, and potential supply chain injection in CI/CD namespaces.

A flaw was found in the protocol mapper and identity resolution components of Keycloak. The issue occurs when a client manager uses hardcoded-claim mappers to override identity claims in sessionless service-account tokens. Because these tokens lack a session ID, Keycloak may incorrectly resolve the token bearer as a different, highly privileged user based on the manipulated claims. This can allow an attacker with limited client management permissions to impersonate a realm administrator and gain full control over the realm.

A flaw was found in the idp-auto-link authenticator of the keycloak-services component, which handles user identity federation. The issue occurs when Keycloak automatically links an incoming identity from an external provider to an existing local account based on an email address without verifying if the provider has validated that email. This can allow an attacker to take over a victim's account by using a matching unverified email address at a brokered provider.

A flaw was found in the Keycloak Admin CLI kcadm tool, which is used by administrators to manage Keycloak servers from the command line. When a custom truststore is provided to verify the server identity, the tool incorrectly accepts any self-signed certificate as long as the hostname matches. This allows a network attacker to impersonate the Keycloak server, steal administrative credentials, and perform unauthorized management actions.